1. Field of the Invention:
The present invention relates to the dewatering of sludge. In particular, the present invention relates to disposable containers for sludge dewatering.
2. Discussion of Background:
Industrial processes sometimes produce wastes in the form of sludges. For both structural and environmental stability and volume reduction purposes, it is usually desirable to separate the aqueous phase, or other, non-aqueous liquid phase, from the solid phase before disposal. Frequently, separation is accomplished by evaporating the water from sludge placed in large settling ponds. At other times, more aggressive techniques are used, including filter pressing that exert substantial pressure on the sludge and thereby reduce the moisture content dramatically and quickly. Another technique is the use of water extraction through layers of filtering materials using a pump to provide suction. A sand layer followed by a gravel layer is known in this technique. See the device described by Riise in U.S. Pat. No. 4,382,863, for example.
Certain types of waste require special handling. In particular, hazardous and radioactive wastes may pose health risks and therefore, special precautions are taken to reduce the exposure of workers to these materials. Levendusky discloses a container for processing and disposal of radioactive wastes in U.S. Pat. No. 4,107,044. In his container, he deploys a network of perforated pipes deployed throughout a quantity of resin beads. Aqueous, radioactive wastes are pumped into the container, and the liquid removed through the pipes. The radioactive ions in the water adhere to the resin beads and remain in the container. When the beads saturate, the container is sealed and transported to a disposal site for burial.
There is considerable political and economic pressure to reduce the volume of wastes, especially "low-level" radioactive wastes. Disposal costs increased dramatically making it important to minimize the amount of waste disposed and, equivalently, assure that as much waste volume per unit container volume is disposed of as possible.
Thus, handling of low-level radioactive wastes must be minimized and the amount of waste per container maximized.